1. Field
The present invention relates to a multi-step press system and, more particularly, to a press die set for use in a multi-step press system that can simultaneously press-form workpieces placed on a plurality of press-forming stations through a single pressing stroke.
2. Discussion of the Related Technology
A press refers to a machine for manufacturing products by shearing, forming and squeezing a material such as a metal plate, a plastic, a fiber and the like. The press is suitable for use in mass production of articles and finds extensive applications in a variety of industrial fields. Press die sets of varying structures are employed in the press for the purpose of cutting, punching, blanking, piercing, bending, drawing and embossing workpieces. Each of the press die sets includes an upper die attached to a ram of the press and a lower die secured to a table thereof. The press die sets are often called a punch, a cutter or other names depending on the functions performed by them.
In the meantime, a multi-step press system is known in the art, which system is designed to load workpieces into a plurality of press-forming stations one after another and then press-form them into final products. The multi-step press system includes a press die comprised of a plurality of transfer dies corresponding to press-forming stations, each of the transfer dies having a set of upper and lower die members.
Such a press die for a multi-step press system is disclosed in Korean Patent Laid-open Publication No. 2000-70458 wherein an upper die member and a lower die member are removably attached to a die holder by means of a clamp. However, this poses a problem in that press die fabrication costs are increased due to the use of the die holder for clamping the upper die member and the lower die member. Another problem is that the task of attaching and removing the upper die member and the lower die member in individual press-forming stations are time-consuming and labor-intensive. A further problem is that the press die becomes expensive due to the difficulties encountered in developing, designing and fabricating the same.
The discussion in this section is to provide general background information, and does not constitute an admission of prior art.